Opinions on using this old insulation

[Keith Avery]

I found someone selling old rigid 4 by 8 insulation on craiglist. It is not pretty and would like some opinions on whether or not I should use it. I have a 30 by 48 pole barn on 8 ft centers and 4 ft truss spacing so installing this would be easier than batts. It is also very cheap. Only want $1.50 per sheet and they have about 150 sheets. I have not seen insulation like this but it is very rigid. It is 2 inches thick and has a lighter out layer on both sides that is obviously fiberglass. The inside is dark red/brown with fiberglass woven through it, but the primary material is very similar to the green foam my Mom used to use to push fake flowers into to make arrangements. I am posting some pictures. I plan on using OSB on the walls after insulation. I have been unable to identify this stuff and want to make sure it isn't dangerous and will be effective.

[Dave Schreib]

No manufacturers markings on it? Seller have any idea how old it is?

At $1.50 per sheet it would be hard to go wrong.

[Keith Avery]

I haven't picked it up yet and only have a small piece. It was in 4 stacks 8 ft tall or so and I couldn't see any labels. Current owner bought it 5 years ago from someone who had ripped it out of some old buildings. He bought about 300 sheets and never used it all. I am sure that I could resell it for what I paid but it will take most of a day to transport back to my place. It is about 30 minutes away and will take at least 4 trips.

[David Roberts,Fitchburg,Ma]

If there are no markings, it might, or might not have the type of R factor new material has. I bought some pieces of 4x4 4" foam R32 (but paid $10 each) it was great in a knee wall that had my forced hot water pipes going thru. What about putting an electric space heater on one side and aim it at the material, put your hand, or even better a thermometer, to see if it actually has an insulating qualities. I am sure there is a scientific test, but something simple might give a quick answer. the size sounds perfect for your situation, I also built 8' on center for my pole barn.If it seems to work, the price sounds great, buy em all, Good luck,

[Eric Gustafson]

That looks a lot like the polyisocyanurate insulation. They sell a version of that at the big box here with foil backing. It has a R value of ~6.5 per inch. Look like a good deal.

[phil harold]

That looks a lot like the polyisocyanurate insulation. They sell a version of that at the big box here with foil backing. It has a R value of ~6.5 per inch. Look like a good deal.

good stuff but is also open cell foam tha can wick and absorb moisture/water
If kept dry works great.
foil is great moisture barrier thats why it is sold with that quite often


price is great
go for it
might want to vapor barier it before the osb

[Mitchell Andrus]

I'm thinking about the gunk that used to be used in building products back in the good old days.... well, even now like the FEMA trailers that can't be used because of the fumes.

I'll postulate a guess that anything bad that might out-gas from this stuff is long gone. Anyone know anything about formaldehyde or similar?
.

[Harry Hagan]

Remember, it’s the dead-air space trapped inside the insulating material that “insulates".

If those spaces are contaminated, the R value will be greatly reduced.

Also, I’d be concerned about moisture condensing between those sheets and your wall and roof sheathing. Might cause rot and mold. Especially with a metal roof.

[Lee Schierer]

I would check the flammability with a propane torch. See if it continues to burn if heated to a high temp and the heat source is removed. I would do this only with a small piece and preferably outside. If it continues to burn, I think I would pass despite the low price.

[Keith Avery]

I am going to give it the torch test. I am sure moisture could be a problem but I didn't mention that the building is already fully enclosed(when built) with double bubble foil which is a radiant barrier. Seems to be quite airtight and I plan to run a dehumidifier all the time to keep humidity low.

[phil harold]

I plan to run a dehumidifier all the time to keep humidity low.

During the summer you might as well run a small widow or wall air conditioner than a dehumidifier
both machines operate the same and cost about the same to operate

only the air conditoner warm coils are on the outside of the building

so you get cooling plus dehumidfication...

[Bill Rogers]

I agree that it looks like polyisocyanurate foam with a fiberglass facer. Seven years ago the R-Value of 2" polyisocyanurate roof insulation was listed as R-12.1 (Long Term Thermal Resistance). Most Iso insulations have a Factory Mutual 1A rating (low flammability, suitable for residential/inhabitated construction).

Bill

[Rob Fisher]

I'll third that it appears to be polyiso, which typically has a good r-value. In the 6 per inch range as previously mentioned. However it is also known to break down quicker than other insulation's. And depending on how old this insulation is, it might not be worth it.

Rob